Data networks have traditionally been wired, either copper or fiber. Wireless spectrum has typically been used for subscriber links, not Data Infrastructure. The advent of micro cells, pico cells, nano cells, and hotspots has made the provisioning of wired Data prohibitively expensive. This is a result of inflexibility of wired networks; cable has to be run to add new points of presence. In many cases, this requires that streets be torn up.
Wireless Data networks can be much more flexible, and hence more economically viable. However, existing wireless Data network architectures limit this flexibility in several ways. One common form of wireless Data networks uses point-to-point radio links, typically operating in the microwave or millimeter wave bands.
Another common form of wireless Data networks use a cellular architecture. These networks are based on frequency reuse. Typically a cellular reuse scheme where the total available frequency spectrum is divided into sub bands, “colors”, which are reused in disjoint geographical areas, “cells”. For example, reuse factors of 4, 7, and 12 are popular. Other systems reuse time, polarization, or code. The disadvantage of all of these fixed, “cellular”, reuse schemes are that they are inefficient, resources are wasted. For example, in a 7 to 1 frequency cellular reuse system, only 1/7-th of the total available frequency spectrum is available in a single cell, even if none of the adjacent cells are being used. Another disadvantage of these frequency reuse schemes is that it is difficult to add more cells in an area of high demand.